Method development for mapping the mold-filling process of thermoplastic compression-molded components with continuous-fiber reinforcement and complex rib structure Methodenentwicklung zur Abbildung des Formfüllprozesses thermoplastischer Pressbauteile mit Endlosfaserverstärkung und komplexer Rippenstruktur

In the context of the protECOlight funding project ('Sustainable and weight-optimized protection structures in the underbody area for vehicles with new drive technology'), in addition to the investigation of sustainable material strategies for the representation of underride guard (UFS) components for BEVs, intensive process investigations and also an accompanying method development for the mapping of component production were also carried out. The latter has a novelty value, since, according to the authors' current state of knowledge, there are no scientific approaches for describing the relevant physical variables and relationships. The component geometry of the UFS in its specific design as a sandwich consisting of continuous fiber and LFT-D molding compound requires a novel manufacturing process in which rib structures can only be filled with molding compound when the LFT-D extrusion compound has locally penetrated the continuous fiber. This process control is the key to robust and efficient production of the component. However, existing methods for simulating mold filling or for determining the required clamping force are not sufficient for mapping the phenomena involved in component filling in the case of this complex geometry. This paper will focus on the basic work on understanding the relationship between component geometry, in particular rib design, and the clamping force required for complete mold filling in the pressing process. The basis for the new findings are the test series for the production of a demonstrator structure and its analysis in combination with the development and evaluation of simulative approaches to describe the complex mold-filling process. Significant aspects that play a role here include the local damage to the continuous-fiber structure under the rib, which were examined and evaluated as a function of the identified parameters. On this experimental basis, together with specially developed analytical models as well as the coupling of mold-filling and forming simulation, qualitative statements can now be made about the fillability of the ribs so that process optimization can take place. In addition, the influence of local flow aids in the tape under the ribs could be shown experimentally as well as simulatively.